An anti-oscillation valve for and in a trap primer to restrict the flow of water from the supply line to an upper chamber of the trap primer and to facilitate the flow of water from the upper chamber to the supply line. The anti-oscillation valve having a body with a water supply bore provided therethrough. The bore includes portions defining an inlet and an outlet. First and second bore shoulders are formed in the bore. A filter screen is retained in engagement with the first bore shoulder. An anti-oscillation valve disc freely rests on the second bore shoulder and is retained between the first bore shoulder and the second bore shoulder. The anti-oscillation valve disc includes a valve disc orifice defined through and communicating the inlet with the outlet.

A method for distributing water from a trap primer to at least one trap. The method includes providing a trap primer having an upper chamber separated by a flexible diaphragm from a lower chamber, and having a resilient gas enclosure located in the lower chamber. Water is provided to the trap primer at a line pressure charging the upper and lower chambers. As a result of a reduction in line pressure, the diaphragm is disengaged from a valve stem opening an orifice and causing the flow of water from the lower chamber to at least one trap.

A method for distributing water from a trap primer to at least one trap. The method includes providing a trap primer having an upper chamber separated by a flexible diaphragm from a lower chamber, and having a resilient gas enclosure located in the lower chamber. Water is provided to the trap primer at a line pressure charging the upper and lower chambers. As a result of a reduction in line pressure, the diaphragm is disengaged from a valve stem opening an orifice and causing the flow of water from the lower chamber to at least one trap.

An embodiment providing one or more improvements includes a trap primer with upper and lower chambers separated by a flexible diaphragm which also interacts with a valve stem to start and stop the flow of water from the trap primer to the trap(s). The lower chamber contains a polymeric foam medium such as a foam ring containing closed cells containing gas or gases. In use, equilibration of water pressures in the upper and lower chambers causes distortion of the foam ring, resulting in equilibration of the gas pressure in the closed cells with that of the chambers. A decrease in line water pressure causes water from the lower chamber to be emitted into the traps.

An embodiment providing one or more improvements includes a trap primer with upper and lower chambers separated by a flexible diaphragm which also interacts with a valve stem to start and stop the flow of water from the trap primer to the trap(s). The lower chamber contains a polymeric foam medium such as a foam ring containing closed cells containing gas or gases. In use, equilibration of water pressures in the upper and lower chambers causes distortion of the foam ring, resulting in equilibration of the gas pressure in the closed cells with that of the chambers. A decrease in line water pressure causes water from the lower chamber to be emitted into the traps.

A waterless trap for use in a drain assembly includes flow enhancing features to promote the vortex water flow of water received in the trap, an improved sealing arrangement to enhance the seal between a seal member and the housing to inhibit sewer gas leaks from an attached drain pipe by maintaining an evaporation barrier that assists in retaining water in a corresponding p-trap, and a plurality of air passages can allow the trap seal to open with ease when the drain pipe is pressurized. These features may be used in combination with one another or may be independently employed.